The broad objectives of this research are to characterize the natural history and tumor kinetics of multiple myeloma and related human neoplasms and to develop more effective treatment. Studies of immunoglobulin synthesis, total body tumor cell number, growth and regression rate, and the tumor stem cell population will be used to accomplish these objectives. A specific idiotypic marker system will be applied to identify as few as the last 5,000 myeloma cells in the body.